A vagina who's sexual activity has been neglected. These vaginas grow teeth and reach out to eat people out of horny desperation. In other words, a pussy gone wild. Variations are the Tyranasaurus Vagina, Mastadon Vagina, Woolly Mammoth Vagina (derrogatory), Hippopodumus Vagina, etc. (Basically anything large and terrifying with teeth will do be creative, however, sabertooth is the most appropriate because of it's derivative from pussy)

Dude! I need to get laid! I'm starting to grow a Sabertooth Vagina below the waist!